J. Phys. Ther. Sci. 29: 585–589, 2017
The Journal of Physical Therapy Science Original Article
Characteristics of patients with hemiparetic stroke who yield highly reliable muscle strength measurements Ken Tomida, RPT1)*, Genichi Tanino, RPT1, 2), Shinya Sasaki, RPT3), Akira Suzuki, RPT1), Sayaka Okamoto, MD1, 4), Shigeru Sonoda, MD1, 2, 4) 1) Fujita
Health University Nanakuri Memorial Hospital: 424-1 Odori-cho, Tsu, Mie 514-1295, Japan Memorial Nanakuri Institute, Fujita Health University, Japan 3) Fujita Health University Hospital, Japan 4) Department of Rehabilitation Medicine II, School of Medicine, Fujita Health University, Japan 2) Fujita
Abstract. [Purpose] Accurate measurement of unaffected lower extremity muscle strength on the unaffected side is useful in patients with hemiparetic stroke; however, muscle strength measurement results in patients with hemiparetic stroke vary greatly compared with those in healthy individuals. The objective of the present study was to determine the characteristics of patients with hemiparetic stroke who yield highly reliable muscle strength measurements. [Subjects and Methods] The subjects were 55 incipient patients with hemiparetic stroke. Muscle strength was measured twice. Based on the measured changes and on error ranges in repeated measurements in previous studies, the subjects were divided into two groups: subjects whose measurement results were within the acceptable range, and those whose measurement results were not within the acceptable range. Logistic regression analysis was performed with this separation of groups as the dependent variable, and demographic data, physical functioning, and functional independence measure (FIM) as independent variables. [Results] From the analysis results, the FIM cognitive subscore was selected as a criterion for patient selection; the cutoff score was 19. [Conclusion] The results of the present study indicated that muscle strength measurements were highly reliable in patients with hemiparetic stroke with an FIM cognitive subscore of ≥19. Key words: Stroke, Muscle strength measurement, Reliability (This article was submitted Nov. 11, 2016, and was accepted Dec. 15, 2016)
INTRODUCTION Lower limb strength on the unaffected side is crucial because of its involvement in sit-to-stand capacity, stand-pivot-sittransfer capacity, gait speed, gait distance, and stair ascent capacity in patients with hemiparetic stroke1). Accurate measurement of the unaffected lower limb strength in patients with hemiparetic stroke is important for assessing impairment, drafting therapeutic strategies, and assessing therapeutic effects. Although manual muscle testing and hand-held dynamometers are simple to use, an isokinetic dynamometer is recommended for measuring muscle strength more reliably2). Using an isokinetic dynamometer, Sole et al. reported that the smallest real difference percentage of isokinetic knee extensor muscle strength in healthy individuals was 15.07%3). However, Flansbjer et al. reported that in patients with hemiparetic stroke, most of whom have a functional independence measure4) (FIM) motor subscore of ≥78, the smallest real difference percentage of isokinetic knee extensor muscle strength on the unaffected side is 26%, which is greater than that in healthy individuals5). Thus, differences in muscle exertion in patients with hemiparetic stroke, even in high-functioning patients, are greater than that in healthy individuals, making measurements less reliable. *Corresponding author. Ken Tomida (E-mail:
[email protected]) ©2017 The Society of Physical Therapy Science. Published by IPEC Inc. This is an open-access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives (by-nc-nd) License .
Table 1. Demographic and clinical data of all subjects Number of patients Age (years) Gender (male/female) Side of paralysis (right/left) Time after onset (days) SIAS-L/E score FIM-M score FIM-C score FIM-COM score FIM-SC score Total units of PT and OT of intervention period Muscle strength of the first measurement (Nm)
55 63.8 ± 12.1 28/27 35/20 35.6 ± 13.2 4.5 ± 4.0 41.0 ± 15.4 21.8 ± 8.2 8.5 ± 3.6 13.2 ± 5.3 51.8 ± 7.5 63.6 ± 35.9
SIAS-L/E: Stroke Impairment Assessment Set Motor L/E; FIM-M: Functional Independence Measure motor subscore; FIM-C: Functional Independence Measure cognitive subscore; FIM-COM: Functional Independence Measure communication; FIM-SC: Functional Independence Measure social cognition
We have examined the types of stroke patients who demonstrate large differences in muscle exertion measurements, leading us to the discovery of a measurement to detect such patients.
SUBJECTS AND METHODS The subjects were incipient patients with hemiparetic stroke who provided consent to participate in the present study; 55 patients remained after excluding those whose muscle strength could not be measured easily, those unable to maintain a sitting position, and those with other functional impairments (Table 1). All subjects underwent the Full-time Integrated Treatment program6), a 7 day/week rehabilitation program of physical and occupational therapy. The present study was approved by the institutional review board of Fujita Health University Nanakuri Memorial Hospital. On day 2 following admission to our hospital, the patients were assessed for age, time from onset until hospitalization (hereafter, “time after onset”), and Stroke Impairment Assessment Set7) Motor lower extremity motor subscore (SIAS-L/E), and FIM (version 3)8). For FIM, we calculated FIM motor (FIM-M) and FIM cognitive (FIM-C) subscores. We then further classified FIM-C into FIM communication (FIM-COM), which is the total score for comprehension and expression; and FIM social cognition (FIM-SC), which is the total score for social interaction, problem solving, and memory. Muscle strength was measured on day 2 after admission to our hospital (hereafter, “first measurement”); muscle strength was measured again (hereafter, “second measurement”) on day 9. The device used to measure muscle strength was Biodex System 3 (Biodex Medical Systems; Shirley, NY, USA); the knee on the unaffected side was extended thrice in the isokinetic mode at 30°/s. The mean peak torque across the three extensions was adopted as the value for muscle strength (Nm). In the second measurement, we examined the total time spent in physical and occupational therapy in the 1-week period after the first measurement. In the present study, the subjects were separated into two groups based on the difference in muscle strength measurements: subjects whose difference was within the acceptable range and were thus considered able to exert muscle strength (hereafter, “Acceptable group”), and subjects whose difference was outside the acceptable range and were thus assumed to be unable or unwilling to exert muscle strength (hereafter, “Unacceptable group”). In separating subjects into groups, the acceptable range of difference was established by combining measurement error ranges in previous studies and potential increases in muscle strength enabled by recovery rehabilitation. The measurement error in repeated measurements with an isokinetic dynamometer in healthy subjects was assumed to be 15%3), whereas the maximum muscle strengthening effect in 1 week (the period between the two muscle strength measurements in the present study) was assumed to be also 15%9). Patients who demonstrated a decrease of more than 15% or an increase of more than 30% in muscle strength from the first measurement to the second measurement were sorted into the Unacceptable group; all other subjects were sorted into the Acceptable group. Statistical analysis was performed by using SPSS Statistics 19 (International Business Machines Corp., Armonk, NY, USA). Logistic regression analysis was performed with muscle strength measurement acceptability (Acceptable group versus Unacceptable group) as the dependent variable. The independent variables consisted of age, SIAS-L/E, FIM-M, FIM-C, muscle strength during the first measurement, and the total units of physical and occupational therapy in the 1-week intervention period. For FIM-COM and FIM-SC, logistic regression analysis was performed with forced entry. Subsequently, receiver operating characteristic (ROC) curves were drawn for both FIM-COM and FIM-SC with the selected variables; the area under the curve (AUC) was calculated, and the Youden index was used to determine the cutoff values. Basic information was 586
J. Phys. Ther. Sci. Vol. 29, No. 4, 2017
Table 2. Demographic and clinical data of the subjects stratified into two groups Number of patients Age (years) Gender (male/female) Side of paralysis (right/left) Time after onset (days) SIAS-L/E score FIM-M score FIM-C score FIM-COM score FIM-SC score Total units of PT and OT of intervention period Muscle strength of first measurement (Nm)
Acceptable group
Unacceptable group
43 63.7 ± 12.8 22/21 26/17 33.3 ± 12.9 4.9 ± 4.2 43.2 ± 15.2 23.7 ± 7.8 9.2 ± 3.4 14.4 ± 5.2 52.2 ± 7.7 68.7 ± 36.4
12 63.9 ± 10.2 6/6 9/3 44.1 ± 10.8 2.9 ± 2.8 32.9 ± 13.7 14.8 ± 5.5 5.9 ± 3.3 8.9 ± 2.9 50.2 ± 7.1 45.6 ± 28.7
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